Key evidence in a public corruption scheme operated by elected officials in a major U.S. county could be scarce because much of it lies in private electronic mail accounts that may be exempt from open records laws.

The case in southern California’s San Bernardino County brings up the controversial issue of what exactly constitutes public records. Can communication between public officials be covered by open records laws if the officials use private electronic mail accounts or devices?

Courts and open records advocates nationwide have expressed that laws do in fact apply to government-related work that is discussed or performed with private electronic mail accounts. However, officials throughout the country have legally fought to keep from the public communication—especially electronic mail—they claim is personal.

Like many states, California’s open records law does not specifically address government-related messages on private computers. Adopted in 1968, the law was updated to cover electronic records, including mail, kept by government agencies but does not include a provision key to San Bernardino’s case.

County investigators claim that the assessor, an elected official who was once chairman of the Board of Supervisors, used his office and publicly paid aides to run an illegal political machine funded by taxpayers. The secret group further orchestrated fraud by awarding a bogus contract to a political consultant friend—for tens of thousands of dollars—who did no work for the county. A city councilman and several other public officials are implicated in the scheme.

Several of the parties involved face criminal charges, but an initial investigation has determined that the crooked officials purposely bypassed open records laws by communicating with instant text messages on mobile devices using private accounts rather than the county server. That means key evidence may tough to obtain.